December, 1932
I N D U S T R I A L A N D E N G I N E E R I 1v G C H E A I I S T R Y
TABLEr-1,
IXSECTICIDAL k T 1 0 N OF PYRETHRUM EXTR.4CTS PREPARED WITH DIF'FERESTPETROLEUM DISTILL.4TES AS COMPARED WITH THATO F PETROLEUM DISTILLATE ALOSE (1929)
PAR&- Xv. LYTIC hf0R-
DISTILLATEBoiling range Gravity TEsTs FLIESPOINT TALITY O F. C. O A . P.I . Sec. %
I -
Pyrethrum extract of distillate 4 Pyrethrum extract of distillate 1 Distillate 1
310-395 (293-374) 49.0 378-516 (367-488) 41.2 378-516 (357-488) 41.2
work. He also wishes to acknowledge the support of the Deep Rock Oil Corporation which financed this research as a Crop Protection Institute Fellowship.
Av
50%
SOLETION
1397
5 5 5
261 316 280
297 170 284
36 54 42
It is clear that the pyrethrum extract made with a relatively ineffective fraction (distillate 4) is distinctly less efficient than that prepared with a more potent fraction (distillate 1). The extract prepared with the low-boiling distillate paralyzes flies much more slo-ivly than that made with the higher-boiling fraction. Furthermore, the final mortality produced by the former was much less (and statistically significant) than that produced by the latter. Even distillate 1 alone was about equal in speed of paralytic action and surpassed in killing power the pyrethrum extract made with distillate 4. Apparently the kerosene base used in preparing pyrethrum extracts is a t least as important, if not more so, than the amount of pyrethrum pori-der used in preparing the extract.
ACKNOWLEDGMENT The author wishes to express his thanks to C. IT. Richardson for his advice and criticism during the progress of the
LITER.4TURE C I T E D
(1) Anonymous, U. 3. N a r y Dept., Bur. Med. Surg., Div. Preventive Med., Bull. 86, 6 (Sept. 15, 1919). (2) Anonymous, Soup, 2, No. 2, 1 9 , 51, 53 (1926). (3) Ibid., 2, No. 3, 51 (1926). (4) Ibid., 5 , No. 7, 109, 111, 133, 135, 137 (1930). (5) Cook, A. J., Mich. State Board d g r . , I?th A n n . Rept., 18771878, 431-8, esp. 434 (1878). (6) Davis, G. C., Ark. Ind. Unir. Agr. Sta., Bull: 15, 1-12 (1890). (7) Fisher, R . A , "Statistical Methods for Research Workers," 3rd ed.. DD. 99-112. Oliver and Bovd. " . 1930. 2, NO,'^, 49 (1926). (8) Fremd, (9) Gillette, C. P., Iowa Agr. Expt. Sta., Bull. 12, 5 3 5 4 9 (1891). (10) Gothard, N.J., Soup, 8, No. 6, 103, 105, 107 (1932). (11) Gruse, W. A , "Petroleum and Its Products," p. 144, McGrawHill, 1928. (12) Moore, IT.,and Graham, S. A . , J . Econ. Entomol., 11, 70-5 (1918). (13) Pannewitz, E., 2. Desinjekt.- u. Gesundh., 23, 465-76 (1031). (13a)Pannewitz, E., Seijennsieder-Ztg., 59 (23). 365-6 (1932). (14) Richardson, H. H., J. Econ. Entomol., 24, 97-105 (1931). (15) Ibid., 24, 763-4 (1931). (16) Ibid., 24, 1098-1106 (1931). (17) Riley, C. V., U. S. Dept. Agr., Rept. Entomol., 1884, 330-4.
RECEIVEDDecember 28, 1931. This paper is part of a thesis presented to the graduate faculty of Iowa State College in partial fulfilment of the requirements for the degree of doctor of philosophy. The author is now with the Bureau of Entomology, U. S. Department of Agriculture, Washington, D . C.
Effect of Sodium Carbonate on LowTemperature Reduction of Iron Ores G. C. WILLIAMSAND R. A. RAGATZ,University of Wisconsin, Madison, Wis.
T
HE low-temperature reThis paper describes the results The presence of sodium carbonate in a carduction of iron Ores has of such experiments. bonaceous reducing mixture markedly influences been d i s c u s s e d in conPrior to initiating the experisiderable detail by Williams (6). the rate Of reductionOf iron Ores as judged by mental work, a s u r v e y of t h e their melallic iron content after reduction. The various processes that have literature was made, but pracThe percentage reduction increases with tembeen tried on a semi-commercial tically no information was found scale are described, and a deon the effect of various cataperature, tivie, and percentage sodium carbonate. tailed discussion of the funda!ytic agents on the reduction of The effect of sodium addition appears mental principles of reduction is iron o r e s i n t h e p r e s e n c e of to be the most marked at 900" C. given. One factor of major imsolid carbon. I n Sweden (1, 6 ) portance in d e t e r m i n i n g t h e where a low-temperature reducsuccess or failure of a low-temperature reduction process is tion process is being operated on a commercial scale, it is the the rate of reduction. The failure of many of the proposed practice to add calcium and magnesium oxides to the mixprocesses may be ascribed, a t least in part, to an unsatisfac- ture of ore and carbonaceous material, but the primary purtory rate of reduction of the ore to metallic iron. is to lower pose of the addition, as in the Sieurin patent (4, From a consideration of the mechanism of energizer action the absorption of sulfur by the reduced sponge iron. Any in the carburization of steel as developed by one of the writers accelerating effect that such additions may have on the rate ( 3 ) , and from a consideration of the probable mechanism of of reduction is not mentioned. the reduction of iron oxides in the presence of solid carbonaWhile the work described in this paper was in progress, ceous material, it seemed probable that those catalytic agents IwasB, Fukusima, and SaitB ( 2 ) published the results of an inwhich produce a definite acceleration in the rate of' carburiza- vestigation on the catalytic effect of various materials on the tion of steel would also exert an accelerating effetL upon the reduction of iron oxides. It was demonstrated that sodium rate of reduction of iron ores in the presence of a solid carbona- carbonate exerts a decided accelerating effect on the rate of ceous reducing agent. As a result of the work on the cata- reduction. However, the degree of reduction of the ore was lytic effect of various materials on the carburization of steel, evaluated on the basis of the oxygen removal rather than by it was shown that sodium carbonate was one of the most active a determination of the quantity of metallic iron formed. In materials. Accordingly, it was decided t o investigate the the experimental work performed by the present writers, the effect of sodium carbonate on the rate of reduction of iron degree of reduction was evaluated on the bask of the metallic ores in the presence of a solid carbonaceous reducing agent. iron formed.
INDUSTRIAL AND ENGINEERING CHEMISTRY
1398
Vol. 24, No. 12
EXPERIMEKTALthat, after weighing and mixing, the entire charge just filled PROCEDURE the retort with little or no tamping necessary. It was decided to employ a ratio of 2 parts of ore to 1 part of Two commercial Ores were used in coke throughout the investigation, and to calculate the perthis investigation, a centage of the catalyst on the total weight of the reducing soft h e m a t i t e ore mixture. That is, a 10 per cent sodium carbonate mixture from the M e s a b a would have the materials present in the ratio of 18 parts of Range, Minn., and ore to 9 parts of coke and 1 part of sodium carbonate, all a d e n s e magnetite taken by weight. An electric muffle furnace with a heating chamber 5 3 / 8 ore from the Lake Champlain district, inches (13.7 cm.) high, 7 l / ~inches (18.2 cm.) wide, and 14 N. Y. S i n c e t h e inches (35.6 cm.) long was used; as an added insurance against rate of reduction is heat loss and large temperature gradients within the furnace, a function of par- a 5-inch (12.7-cm.) plug of insulating brick faced on the inside ticle size as well as with a l/d-inch (0.6-cm.) steel plate was placed in the front of o t h e r f a c t o r s , opening and used in conjunction with the insulated door, A the ore was crushed rack held a group of four retorts centrally placed in the reand carefully sized maining heating space, while a chromel-alumel thermocouple before use. T h e placed directly above the center of the group and connected material used passed to a Leeds and Northrup potentiometric-type controller a 2 8-m e s h si e v e recorder served as a temperature regulator. ~ ~ ~ E~~~~ ~ ~ soDIuM = 1 cAR. Reduction time is specified in this paper as the total time (Tyler series) but BONATE ON REDUCTION OF HEMATITE. (Time, 3.5 hours) was held on a 35- in the furnace. The retorts were placed in the furnace when mesh sieve. After it was a t the desired temperature, and, after the required period of time had elapsed, they were sizing, the ore was mixed and then removed and cooled in air. After the heated a t 112' C. for 2 hours to elimiattainment of the desired temperature, nate m o i s t u r e . A second sizing rewhich required approximately 6 minutes, moved the small quantity of fine mathe temperature record showed a regulaterial formed subsequent to the first tion within d2.5" C. siaing. An analysis of the sized and After cooling, the retorts were opened dried ores showed an iron content of and the contents removed for inspecI 56.28 per cent for the hematite and tion and separation. The separation of 62.46 per cent for the magnetite. coke and catalyst from the reduced maThe s o d i u m c a r b o n a t e w a s c. p. $ terial was accomplished by a magnetic grade, and was p u l v e r i z e d to pass a 100-mesh sieve (Tyler series). Previous separation and a sieving operation. It has been the policy of the writers 2 to use in a test, the material was heated to evaluate the degree of reduction on f o r o n e h o u r a t 112' C. to r e m o v e the basis of the metallic iron formed, moisture. rather than upon the oxygen removed The carbonaceous reducing agent Kas from the ore. I n this paper, percentage a metallurgical coke of the following reduction is the term given to the ratio average proximate analysis on the dry of m e t a l l i c i r o n to total iron, multibasis: plied by 100. This n e c e s s i t a t e d an % % analysis of the reduced material from 7.19 1.48 Ash Volatile matter Fixed carbon
91.33
Sulfur
0.51
FIGURE2. EFFECT OF SODIUM CARI n mixing the sized ore and powdered ~ i ? ~ \ u ~ $ 'MAG~ , ~ sodium carbonate with coke of various sizes, it was found that minimum segregation of ore and sodium carbonate occurred when the coke e a c h r e t o r t for both was sized to pass a 35-mesh sieve but was held on a 100-mesh metallic and total iron. sieve (Tyler series). Accordingly, coke sized in this manner Total i r o n w a s dewas used in all experimental work. t e r m i n e d by t h e faThe retorts, '/d-inch (0.6-cm.) wrought iron nipples, 4 inches m i 1i a r permanganate (10.2 cm.) long and capped on each end, were chosen for con- method. Metallic iron venience and reproducibility. The nipples and caps were was determined accordthoroughly washed in high-test gasoline to remove all ad- ing to the method recherent grease or oil. They were then heated to 900" C. and o m m e n d e d by the held for 10 minutes, with a final cooling in air. This treat- Bureau of Mines (7). ment eliminated traces of grease or oil and formed a hard A weighed sample of thin adherent scale on the interior of the retort. Fresh re- t h e r e d u c e d o r e was torts were used for all runs. digested in an excess of The mixing technic employed involved a preliminary thor- neutral copper sulfate ough dispersion of the sodium carbonate in the fine coke, solution. The l i q u i d followed by the addition of the ore and a second mixing. was atered off, aciduThis sequence of operations not only produced a uniform car- lated with bonate distribution, but prevented segregation of the heavy a n d d i g e s t e d w i t h ore particles. The amounts of the materials were so chosen metallic aluminum to
ztz
90
1
1
I
I
9
, FIGURE3. EFFECT OF TEMPERATURE ON REDUCTION OF HEMATITE. (Time, 3.5 hours)
I N D U S T R I A L A 3 D E N G I N E E R I N G C H E 31 I S T R Y
December, 1932
I. EFFECTO F
TABLE
SODIUM C.4RBOSlTE I n mixture REDUCTIOX IH 2.5 H O ~ R S of ore and In Hematite Magnetite reducing reducing TEMP. agent agent ore ore O C .
70
800
0
4
8
. 850
12
0
4
8
70
% 0
1.37
...
... ...
.
...
2.82
4.35
...
,..
...
...
...
...
. I .
900
0
0
0.675
1.37
2.08
...
...
Av.
0.35 0.33 0.34
8
2.82
BY.
1.78 1.27 1.53
33.0 34.1
1.41 0.92 4 v . 1.17
0.44 0.38 0.41
37.8 52.4 48.8 38.2 A v . 44.3
1.51 0.72 4v. 1.12
0.44
"c
n
R
... ... ... Av. 34.7
10
3.57
...
0.44
...
36.5 45.5 35.6
32.2 39.0 ,..
33.6
39.2
35.6
60.0 73.3
55.4 57.5
Av. 55.0
34.2 51.1 37.8 36.8 43.6 40.7
66.7
56.5
41.4 57.9 65.5 55.1 . I .
...
... ...
... ...
...
...
... ...
...
...
1.64 1.83 1.74
0.44 0.58 0.51
57.7 53.6 55.7
84.7 78.0 81.4
65.8 63.3 64.6
AT.
1.05 1.12 1.os
75.4 57.0 Av. 6 6 . 2
14
5.15
... ...
7.69 12.51
...
4.57 4.26 9.16 12.65 12.30 8.59
5.73 4.00 10.36 12.20
63.1 70.5 Av. 6 6 . 8
86.1 87.4 86.8
73.0 82.0 77.5
50.5 36.5 48.0
23.2 18.4
63.3 62.5
...
... ...
Av. 4 5 . 0
20.8
62.9
33.1 31.7 38.8 40.3 36.0
16.38 19,05 15.25 16.89
12.3
49.9 64.5
22.8 29.2
47.5 43.3
50.0 59.5 61.7 57.1
9.14 13.98
32.0
...
47.7
...
..,
... ... ...
... ... ... ... ...
... ..,
... ...
26.2 12.65 27.8 15.21 Av. 22.97 44.1 45.9 Av. 45.0
...
41.7 31.6 37.1
7.61 7.10 7.36
13.00 4.95
23.9 16.7 15.8 18.8
9.0
... ...
1.37
2.08
5.36 6.44
2.82
...
11.1 16.9
...
precipitate the excess of copper. After filtering, the liquid was titrated with potassium permanganate solution.
DISCUSSION OF RESULTS The scope of this investigation was such as to include the effect of additive amounts of sodium carbonate varying from 0 to 14 per cent of the reducing mixture. Temperatures were varied from 800" to 950" C. by 50" C. interv:tls, and in the majority of cases both 2.5- and 3.5-hour runs were made on each ore. Results are tabulated in Table I and are shown graphically in Figures 1 to 6. Figures 1 and 2 represent a direct plot of the average values given in Table I for a reduction period of 3.5 hours; Figures 3 and 4 were obtained from these average curves. In Figure 3, percentage reduction of hematite ore is plotted against temperature for the various mixtures a t a constant reduction time of 3.5 hours. It is seen that for a plain carbonaceous mixture there is no appreciable yield of metallic iron until a temperature of 900" C. is used, but that a further increase in temperature has a marked effect on the results.
26.0
72.6 68.0
45.0 40.1
89.8 82.1
,..
...
, . I
Av. 7 0 . 3
42.6
86.0
76.6
... ...
48.3 55.7
96.0 88.1
4 v . 76.6
52.0
92.1
85.6 91.0
61.0 55.2
90.5 94.6 91.1
Av. 8 8 . 8
58.1
92.1
... ... ...
...
...
...
45.4
63.3 64.3 66.0 64.5 61.5 57.5 91.7 88.6 74.8
91.0 74.0 84.5 94.2 9 5 . 0 Av. 7 9 . 3 .Iv.93.4 ...
10
3.57
75.0 94.0 59.6 90.0 Av. 9 2 . 0 4v. 6 7 . 3
...
...
12
4.35
99.4 99.1 Av. 9 9 . 3
85.3 75.0 80.2
97.5 98.7 98.1
85,5 88.0 86.8
14
5.15
99.2 98.8 Av. 9 9 . 0
84.3 77.0 80.7
99.0 98.5 98.8
95.0 95.5 95.3
14.0 33.0 23.8 28.4
AV. 57.2
... ...
...
...
84.0 83.2 70.0 79.1
...
53.2
19.1 14.9 17.0
21.5 18.5 20.0
4
...
2.90 1.98 2.44
41.0 40.1 Av. 40.5
0.675
...
63.2
11.13 12.12 .9v. 11.63
Av. 1 9 . 8
2
...
5.90
...
...
36.8
10.2
19.0 20.6
0
21.8 17.1
11.4 9.0
...
0
...
2.84 2.36 2.74 2.08 2.50
...
950
8.07
12.2 8.07 10.91 7.39 Av. 9 . 6 4
...
6
70 2.19
4.35
... ... 5.15
"0 6.3
12
.4v. 11.56
14
oc. 900
4v.
...
4.35
% 0.33 0.38 0.36
0.38 0.40 0.39
Av. 10.10
12
% 1.67 1.52 1.59
REDCCTIOS I N 3.5 HOURS Hematite Maanetite ore ore
1.40 1.25 1.33
1.37
3.57
IRON O R E S
SODIUM CARBONATE In mixture REDUCTIOH In of ore and IS 2.5 HonRa reduoine reducine Hematite .Maenetite TEMP. agentagentore ore
... ...
.... .. ...
10
RATEO F REDUCTIOU OF
1.25 1.11 1.18
0
2.82
... ...
.
REDPCTION I N 3 5 HOCRS Hematile Magnetite ore ore
70
... ... I
SODICM CARBOSATE 03
1399
The addition of sodium carbonate even up to the maximum value had a negligible effect on the metallic iron produced when the temperature was a t 800' C. However, it would be wrong to say that there had been no effect a t all, for, while the carbonate-free mixture was decidedly magnetic after reduction, the degree of magnetic susceptibility decreased with the sodium carbonate increase until the material of highest carbonate content was practically nonmagnetic. This indicates that when no sodium carbonate is present, the nonmagnetic hematite is largely converted into magnetite. The addition of sodium carbonate in progressively larger amounts results in a further conversion of magnetite into a nonmagnetic lower oxide with a consequent decrease in magnetism. Thus, even though the addition of sodium carbonate has no effect upon the yield of metallic iron a t 800" C., it does influence the quantity of oxygen removed. The trend of the curves appears to be similar, and the general slope the same. The asymptotic approach to a 100 per cent reduction is evident, and the attainment of over 95 per cent metallic iron in the high sodium carbonate runs is quite
1400
I N D US T R I A L l A N D E N G I N E E R I N G C H E M I S T R Y
FIQURE 4. EFFECTOF TEMPERATURE ON REDUCTION OF MAQNETITE.
(Time, 3.5 hours)
FIGURE 5. EFFECT OF TINEON REDUCTION OF HEMATITE
above that expected from experiments of previous investigators with pure carbon. The writers specifically wish to point out the great effect of a 14 per cent sodium carbonate addition to a mixture held a t 900" C . At this temperature the percentage reduction changes from 10 per cent when no sodium carbonate is used to 88 per cent when 14 per cent sodium carbonate is present in the reducing mixture, a net increase of 78 per cent. Figure 4 represents the results obtained in a similar manner to Figure 3 but by the use of magnetite ore. The same tendencies are evident, but the actual numerical values reflect the greater difficulty of reducing this much denser material. Some doubt has been cast on the 850' C. values for 12 and 14 per cent sodium carbonate mixtures, for, when comparing all magnetite values with their corresponding hematite points, these two alone lie above the hematite curves. The results in this region were extremely erratic, and, although a weighted average was taken, the accuracy is not comparable with the other values. It was considered that in this range the extreme sensitivity of the systems caused the variations noted. Figure 5 shows the effect of time on the various hematite mixtures a t the different temperatures; 2.5 and 3.5 hours were used in these comparable runs. The effect of 1 hour additional time is slight on the high and low values of percentage reduction. The increased time tends to accentuate the catalytic effect and is shown by the increased slope of the 3.5-hour curve over the slope of the corresponding 2.5-hour curve. Two curves have not been drawn for 850' C., for the variations are not outside the limit of error in this region, and therefore both may be approximated by the same line. Figure 6 is a direct plot of the 2.5- and 3.5-hour values ob-
COALMINE ACCIDENTS LOWESTOF CENTURY. A lower accident-rate in the coal mines of the United States for 1932 than was attained even in 1931, when the lowest coal-mine accidentrate of the century was recorded, is indicated, according to Scott Turner, director of the Bureau of Mines, in his annual report. Rock-dusting of bituminous-coal mines, lon advocated by the bureau a~ a preventive of widespread expfosions, stopped a t least two coal-mine explosions in the past fiscal year, with a probable saving of many lives. During the year, approximately 100,000 c o m e s of training in first-aid or mine-rescue methods were given by the bureau in 702 communities in 36 states and
Vol. 24, No. 12
FIGURE 6. EFFECTOF TIMEON REDUCTXON OF
MAGNETITE
tained for magnetite. The effect of time is more marked a t both temperatures, and is more definite than with the hematite ore. The greater density of this ore as compared to the intermediate product of a hematite reduction offers an explanation for this behavior. While this paper is confined entirely to the catalytic effect of sodium carbonate, it is probable that other materials will exert a similar effect. It may be predicted tentatively that substances which have an energizing effect on the carburization of steel will also accelerate the rate of reduction of iron ores. Formulation of a theory to explain the mechanism of the action of sodium carbonate must await further experiments with a greater variety of materials.
ACKNOWLEDGMENT Thanks are due to 0. L. Kowalke for his helpful suggestions and criticisms, and to H. H. Darbo for his assistance with the analytical work.
LITERATURE CITED (1) Hoeganaes-Billesholms, A,-B., Swedish Patent 58,178 (Feb. 4, 1925). (2) Iwas6, Fukusima, and S d b . Kintoku no KenkGu, 8 (June 20, 1931). (3) Ragatz, R. A., and Kowalke. 0. L., Metals & Allogs, 2, 290, 343 (1931). (4) Sieurin, S. E.,U. S. Patent 1,714,280 (May 2, 1927). (5) Williams, C. E., Bur. Mines, Bull. 270 (1927). (6) Ibid., p. 15. (7) Ibid., p. 75. RECEIVED July 13, 1932.
Alaska, making-a total of 681,145 persons so trained by the bureau. Good progress was also made in the bureau's investigations designed to bring about cheaper and better mining and metallurgical methods, to enable domestic producers of metals to meet the competition of richer deposits in other parts of the world. Largely as a result of the bureau's efforts, domestic potash supplies are being mined on a large scale. Methods for recovering phosphate heretofore wasted have been devised. Large-scale production of helium a t costs lower than ever before attained was achieved.
